Field of the Invention
Embodiments in accordance with the present invention relate generally to photoimageable compositions containing certain photobase generators (PBG) for forming microelectronic and/or optoelectronic devices and assemblies thereof, and more specifically to compositions encompassing polymers derived from olefinic monomers, such as norbornene (NB) and/or styrene, and maleic anhydride that are inexpensive yet exhibit improved properties, including low wafer stress and better thermo-mechanical properties.
Description of the Art
Organic polymer materials are increasingly being used in the microelectronics and optoelectronics industries for a variety of applications. For example, the uses for such organic polymer materials include interlevel dielectrics, redistribution layers (RDL), stress buffer layers, chip stacking and/or bonding, leveling or planarization layers, alpha-particle barriers, passivation layers, among others, in the fabrication of a variety of microelectronic and optoelectronic devices. Where such organic polymer materials are photosensitive, thus self-imageable, and therefore, offer additional advantage of reducing the number of processing steps required for the use of such layers and structures made therefrom. Additionally, such organic polymer materials enable the direct adhesive bonding of devices and device components to form various structures. Such devices include microelectromechanical systems (MEMS), microoptoelectromechanical systems (MOEMS) and the semiconductor device encompassing a complementary metal oxide semiconductor (CMOS) image sensor dam structure, and the like.
While certain of the currently available organic photosensitive compositions are used in some of the aforementioned applications, there is still a need for organic photosensitive compositions which are aqueous negative or positive tone developable especially in such applications as RDL, chip stacking/bonding and CMOS, where there is a growing concern to avoid solvents as the increase demand in such applications has resulted in more solvent waste. At the same time any new aqueous developable compositions should still feature same or better properties than the currently used solvent developable compositions. In particular, several of the current compositions utilize polymers such as polyimide, benzocyclobutenes (BCB) and silicones are expensive, and some of which utilize solvents for developing.
Accordingly, there is still a need for lower cost aqueous developable negative or positive tone compositions which feature better properties, such as for example, i) lower temperature curing which still maintains pattern integrity, ii) improved thermo-mechanical properties, iii) improved elongation to break (ETB), and iv) lower wafer stress, just to name a few.